Anagram test: case-insensitivity must go both ways

Previously it was enough to normalize just the subject.

This also adds the missing case-insensitivity test to some languages. But I'm not sure if that's a good policy going forward, that you have to update all languages. What could have been a quick fix took a while, so I will be more reluctant to fix small things in future.

If the problem never pops up in say the Clojure community, perhaps because it never happens in that language or nobody makes that mistake or nobody spots it, the value of that test is kind of low. The value of getting more spec fixes for languages where a problem does pop up is higher.